NASA's Green Flight Challenge: The Ultimate Flying Car Competition

Instead of waiting for the inevitable aircraft X Prize, engineers can bring their sustainable plane ideas to NASA and the Comparative Aircraft Flight Efficiency Foundation's Green Flight Challenge. The contest, which comes with $1.5 million in reward money, aims to find a low-cost personal air vehicle (read: flying car-like contraption) that averages at least 100 mph on a 200-mile flight, all while achieving over 200 passenger miles per gallon. Other requirements include a short take off, quiet operation, and the ability to drive around on the ground. Oh, and NASA and CAFE would also prefer that regular car drivers can operate the thing. A seperate $150,000 prize for the best score by a bio-fueled aircraft will also be doled out.

One potential entrant is Pipistril, a company working on a small battery-powered glider that flies at up to 6,000 feet. But whether Pipistril is even allowed to enter remains to be seen, as NASA is only accepting 18 competitors into the race, and teams have until May 30, 2011 to prepare.

It's hard to imagine a day when personal aircraft vehicles will become the norm, let alone the day when they are more efficient than driving. After all, mid-air collisions are far more deadly than car crashes, and terrorism concerns are unlikely to be quelled anytime soon. Fortunately, NASA and CAFE imagine other applications for their winning PAV: Air-Taxis, Unmanned Aerial Surveillance, and homeland security surveillance. Air Taxis seem like the most innovative application—just imagine zipping from city to city in quiet, emissions-free flying cars.